.top-header {
    width: 100%;

    /* 设置固定定位 */
    position: fixed;
    top: 0;

    /* 该盒子位于最上层 不要被其它盒子覆盖 */
    z-index: 3;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 20px;
    background-color: #fff;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);

    .logo {
        display: flex;
        align-items: center;

        h1 {
            margin-left: 8px;
            color: #1890ff;
            font-size: 30px;
            font-weight: bold;
        }
    }

    .right {
        display: flex;
        align-items: center;
    }
    .user-info{
        display: flex;
        align-items: center;
        margin-right: 20px;
        .username{
            margin-left: 8px;
        }
    }

}